Output performance of a dye-doped sol-gel silica laser in the near UV

Abstract

Visibly transparent near-UV dye (Exalite 377E)-doped silica in the form of parallelepiped were prepared by the low-temperature sol-gel process. The laser output performance of dye-doped sol-gel silica samples pumped by a short pulse (1 ns) N2 laser at 337 nm was reported. With a grating as the wavelength selection element, the laser was tuned from 367 to 387 nm with a laser linewidth of 2 nm. Using a resonator cavity consisting of two flat mirrors, the sol-gel laser showed a slope efficiency of 34.7% and a pump energy threshold of 20 μJ. The variation of sol-gel laser energy output as a function of the number of pulses under repetitive N2 laser excitation was investigated. The laser output energy decreased initially with the number of shots. The output energy recovered to its original intensity after a ten minute interruption in pumping. In this way, the dye-doped samples showed no signs of long term degradation after being irradiated at 337 nm for tens of thousand shots.